Aberdeen's crisis deepened as Dundee rose off the bottom of the Scottish Premiership with their first league win of the season.
Stephen Glass' side are now 10 games without victory, the last five of which have been defeats.
Goals from Leigh Griffiths and Luke McCowan piled more pressure on beleaguered manager Glass.
And although Christian Ramirez pulled one back, the visitors could not find a second to salvage a point.
October's fixture list offers little respite, with Hibernian, Rangers and Hearts up next for Aberdeen.
For Dundee manager James McPake, after just three points all season, his side doubled their tally to lift themselves three points clear of Ross County.
However, the one sour note was the loss of Shaun Byrne to injury, with the midfielder taken off on a stretcher.
It may have been ninth against bottom, but it felt like a huge occasion. An evening kick-off in order to entice an American TV audience, and both sides on a run of four consecutive defeats and desperately needing an upturn in fortunes. This one mattered.
The inclusion of Griffiths and Charlie Adam in the Dundee starting line-up was much vaunted, but it was another change - McCowan - who could have opened the scoring within the first minute, only for Aberdeen goalkeeper Gary Woods to push away his goalbound effort.
That suggested a thriller was ahead. Instead the sides exchanged a glut of wasted efforts as both showed why they have been struggling.
McCowan, Adam and Paul McMullan all failed to hit the target for the home team. Jack Mackenzie, Lewis Ferguson and Ryan Hedges should have done better at the other end.
Aberdeen did come close to an opener when Ramirez met a Calvin Ramsay corner with a diving header, only for Griffiths to block his effort on the line.
That showed some signs of improvement for the visitors, but from their own attack they were cut open as Dundee took the lead.
Hedges tried a through ball that was blocked. Dundee countered with McMullan launching a long ball forward to Griffiths, who beat the offside trap and lashed low past Woods.
Ferguson had a shot tipped wide for Aberdeen, but their response was slow and cumbersome, and soon Dundee deservedly doubled their advantage.
The ball was played into the path of McCowan on the edge of the box and he picked his spot with a fine low finish inside the far post.
Aberdeen looked a beaten side, with no spark or imagination in them. But as the Dundee fans mocked the visitors, with Glass and captain Scott Brown the main targets, the Pittodrie men got a break to reignite the game.
MacKenzie sent a ball to the far post that wasn't dealt with, and Ramirez knocked it back across and over the line from a tight angle.
Suddenly the visitors appeared a threat. Substitute Niall McGinn cut inside his marker and forced goalkeeper Adam Legzdins to push his effort over the bar.
The game was twice stopped for lengthy treatment needed for Dundee pair Lee Ashcroft and Byrne, the latter coming off second best in a challenge with Declan Gallagher.
Tempers frayed on the sidelines. Aberdeen goalkeeping coach Gordon Marshall was sent to the stand, and was soon followed by Dundee manager McPake after the home bench refused to give the ball back at an Aberdeen throw-in, with young defender MacKenzie ending up on the ground in the melee.
Brown had a deflected shot saved, but for all Aberdeen's possession that was as close as they would come as Dundee swatted away their late attempts, picking up a first win over the Pittodrie side since 2014.
Man of the match - Charlie Adam
What did we learn?
Dundee manager McPake believed his side just needed to start taking their chances to rise up the table. They had few opportunities, but took the two that came their way and battled for every ball to ensure they wouldn't relinquish the points.
Aberdeen started slowly and only found the fight needed when already 2-0 down. What will worry fans is that despite the quality on the pitch, they can't get the best out of them.
And they looked rudderless while continuing to leak goals at the back, now shipping seven in their last three games.
What did they say?
Dundee manager James McPake: "We've seen that performance time and time again, we've seen that effort, we deserved that tonight.
"I think I played the last time we beat Aberdeen, so that shows just how big a task and how big a turn that has been."
Aberdeen manager Stephen Glass: "Same story as it has been all season. Not effective enough at the top despite having the bulk of the ball, and switching off defensively against good players.
"You can only try and improve the players and that's the job that's here. You've got to highlight the bits they're doing wrong and hope it stops happening. It's been happening for far too long this season on far too many occasions, giving teams easy opportunities."
Dundee are away to high-flying Hearts in the Scottish Premiership on Saturday (15:00 BST), while Aberdeen host the other side of Edinburgh, Hibernian (15:00).